Patients with Chronic Kidney Disease (CKD) are characterized by low levels of physical function and physical inactivity. It is possible that kidne dysfunction has an additive effect on the decrement in functioning and mobility that is associated with aging. This proposal is for a pilot study to acquire data that will inform the design, sample size, and appropriate measures for a larger longitudinal trial of physical functioning, mobility and physical activity in older patients with CKD. The aims of this study are a) to use the International Classification of Functioning (ICF) to guide measurement of physical function and mobility in older patients with CKD and b) to test the feasibility and responses to an independent home walking intervention in older patients with CKD. The study will use a blend of qualitative and quantitative measures to assess the effectiveness of the intervention, and will randomize 80 patients > 60 years to the walking intervention. The data will be used to estimate effect size for determining sample size needed for a larger randomized trial. The data can also be used to guide for measurement of physical functioning and mobility in clinical practice and for recommending walking to maintain mobility. Assessment of physical function and recommendation for physical activity are not part of the routine management of patients with CKD, so there is a critical need to for further study this clinically important and sorely neglecte aspect of patient care in CKD. The use of the ICF framework moves the focus of research away from clinical and mortality outcomes to those that are of significant importance to patients. The testing of measures of physical function for use in clinical practice moves patient care beyond a focus on laboratory biomarkers to using measures that will provide more in-depth understanding of overall health. The testing of the effects of a walking intervention will inform design of futur large-scale studies as well as clinical practice.